THE STRUGGLE FOR EXISTENCE 87 



The position which we are seeking to define and 

 defend is this. The concept " struggle for exist- 

 ence " is wider than is suggested by the words 

 taken literally. It is a function of many in- 

 dependent variables. It expresses the reaction of 

 living creatures to their limitations and difficulties. 

 It means that living is rarely drifting, except for 

 parasites. The physical world is careless of life; 

 there is an extraordinary abundance of life ; the 

 river is always surging up to its embankments ; 

 love calls, hunger calls, and there is often no satis- 

 faction ; there are many critical moments in growth 

 and development, many risks of falling through 

 holes in the Mirza bridge ; the living creature has 

 a will of its own a will to live, all this, and 

 more, may be usefully condensed in the formula 

 " struggle for existence." 



Our thesis is that we have the struggle for exist- 

 ence wherever living creatures press up against 

 limiting conditions ; wherever living creatures, with 

 their powers of growing and multiplying, thrusting 

 and parrying, changing and being changed, do in 

 any way say, " We will live/' 



The living creature is by its very essence asser- 

 tive. If it cannot do anything else it will multiply. 

 Life is an endeavour ; it expands, it intrudes itself, 

 it protests against limitations. One living creature 

 presses upon another, competes with another, eats 

 another. And for all this thrust and parry between 

 living creatures and their limitations we use the 

 formula-phrase "struggle for existence." Surely 

 Darwin had this broad conception vividly in mind 

 when he used that strange metaphor : " Nature 

 may be compared to a surface on which rest 

 ten thousand sharp wedges touching each other 



